docs: def get_or_create(self, write_concern=None, auto_save=True,
                        *q_objs, **query):
          """Retrieve unique object or create, if it doesn't exist.
  
          Returns a tuple of ``(object, created)``, where ``object`` is
          the retrieved or created object and ``created`` is a boolean
          specifying whether a new object was created.
  
          Taken back from:
  
          https://github.com/MongoEngine/mongoengine/
          pull/1029/files#diff-05c70acbd0634d6d05e4a6e3a9b7d66b
          """
          defaults = query.pop('defaults', {})
          try:
              doc = self.get(*q_objs, **query)
              return doc, False
          except self._document.DoesNotExist:
              query.update(defaults)
              doc = self._document(**query)
  
              if auto_save:
                  doc.save(write_concern=write_concern)
              return doc, True